Navigating VMware Migration: From Planning to Execution

Many users are concerned about VM migration when planning to replace VMware. A well-planned migration strategy helps reduce risks and ensures a smooth transition to a new virtualization platform. In this blog, we will dive into the entire process of migrating VMs from VMware to Arcfra using the Arcfra Migration Tool. We cover how to assess VM compatibility, build a migration plan, validate the environment, perform a pre-migration test, and execute the final cutover with minimal disruption.

Step 1 — Make sure the source VM is suitable for migration via migration tools

Not all VMs are suitable for cross-hypervisor migration through migration tools.

• VMs with shared virtual disks (e.g. Oracle RAC): Migration of shared disks is not supported by Arcfra Migration Tool nor by vMotion.
• VDI (e.g. Horizon View and Citrix XenDesktop deployed VMs): These VMs cannot be migrated via the Arcfra Migration Tool or vMotion.
• AD Domain Controller VMs: Since this type of VM is strictly bound to hardware information, v2v migration may cause improper AD services.
• Incompatible operating systems: Arcfra Migration Tool cannot migrate VMs on some old or niche operating systems. Please contact Arcfra technicians for detailed information.

These VMs need to be migrated through manual operations.

Step 2 — Make a Migration Plan

Gather VM Information

Before making a migration plan, you need to know the basics of your current VMware VMs. Inventory information for VMs can be exported from VMware vCenter through the following steps:

• Log into the vSphere Client.
• Select Inventory List Overview.
• Click the Virtual Machines tab to display a list of all VMs, and then filter as appropriate.

Typical information that needs to be collected includes CPU, memory, memory utilization, provisioned space, used space, number of network cards, port groups, and so on. The purpose of this session is to understand the overall resource requirements of the virtualized environment. Therefore, the new cluster can be configured based on the total resources required by the VMs to be migrated.

Arrange Migration Windows

For Arcfra Migration Tool, source VM can run normally during full data transfer and manual synchronization of incremental data, meaning that there will be no impact on running business services. However, source VM needs to be shut down for a while for the final incremental data synchronization. Therefore, users need to schedule a downtime window for the migration project.

• Dev/Test VMs can be migrated during business hours.
• VMs running business services are suggested to be migrated during off-peak hours, which will prevent business services from performance degradation caused by the migration.
• To reduce the downtime and final delivery time of business systems, users can manually synchronize the incremental data generated by source VM to target end after the full data transfer is completed. This will be performed online, and the time interval of incremental migration can be adjusted according to the business requirements and network conditions. >>Learn more
• The final phase of VM migration involves a manual shutdown of source VM to perform the switchover. Therefore, users need to carefully arrange the downtime window. With Arcfra Migration Tool, in most cases, the downtime window will not exceed 30 minutes. But it may extend if there is a large amount of incremental data to transfer (the length of downtime is determined by the amount of incremental data and the efficiency of network transmission).

Check Compatibility

Since the migration tool bridges the VMware and another hypervisor, the migration tool’s compatibility with the vCenter/ESXi version, the VM operating system, the CPU architecture, and the VMware virtual switch type is critical to ensuring a smooth migration. Currently, some migration tools cannot support VMs based on vSphere Distributed Switch (VDS), but only the standard switch fabric (VSS). However, migrating VMs from VSS to VDS may cause business network disruption, making these migration tools less effective.

At present, the Arcfra Migration Tool is compatible with a wide range of source and target environments, specifically as follows:

1. Compatibility with vCenter Edition/ESXi Edition

Arcfra Migration Tool can set vCenter and ESXi host (in scenarios where vCenter is not deployed) as the source site, but it does not support all vCenter/ESXi versions. For example, the compatibility list of Arcfra Migration Tool 1.6 is shown below.

Notably, Arcfra Migration Tool is compatible with a wider range of ESXi versions compared to vCenter versions. Therefore, when trying to migrate VMs from an older version of a VMware cluster, users can associate to ESXi host instead of vCenter.

2. Compatibility with VM Guest OS

Arcfra Migration Tool has been adapted to a wide range of operating systems including CentOS, Windows Server, Redhat, Linux, Ubuntu, etc. Please make sure the VM Guest OS is included in the Arcfra‘s OS Compatibility List before the migration. If your Guest OS is not included in the list, please contact Arcfra professionals.

3. Compatibility with server chips

Arcfra Migration Tool supports Intel/AMD x86_64 architecture chips on both the source (VMware) and the target (ACOS) clusters.

In addition, Arcfra Migration Tool enables VM migration based on the vSphere Distributed Switch architecture.

Make Migration Schedule

After confirming the migration time window and compatibility, a detailed migration schedule can be created. Currently, the maximum number of migration tasks created by Arcfra Migration Tool is 30, with each task supporting up to 5 concurrent VM migrations. It also supports setting task queues.

During the migration, users need to control the number of concurrent tasks according to the migration bandwidth. If the bandwidth utilization becomes too high, the migration will be interrupted or fail. For example, if the migration network bandwidth is 1G, the recommended number of concurrent tasks will be 1 or 2. If the migration network bandwidth is 10G, the number of concurrent tasks can be set to 5 (also need to take the original cluster performance into account).

The migration order can be sorted according to the importance of the business running on the VMs from low to high and the disk space from small to large. In addition, it is recommended to arrange a pre-migration (using VMs that do not contain real businesses) before the formal migration to get familiar with the whole migration process.

Step 3 — Configuration and Environment Inspection

Install Migration Tool

Install the Arcfra Migration Tool on the source or target site that meets the compatibility requirements.

Enhance VM Migration Efficiency

Migration efficiency depends on storage performance, deployment design, and network connectivity. Arcfra provides practical methods to optimize migration throughput and reduce overall project time. Pre-migration testing can help validate expected performance and refine the migration plan. >>Learn more

Environmental Inspections

Before pre-migration and formal migration, the last thing to do is to ensure migration environment configurations.

• Check network connectivity: This is basically about the network connectivity between the migration tool and vCenter/ESXi hosts. For instance, if there are firewalls between them, you need to open the relevant ports in advance.
• Check if the vCenter and ESXi hosts are associated with each other via DNS domain names: If so, you need to make sure that the migration tool and the destination cluster and host are all interpreting the DNS domain names properly.
• Check whether the VM to be migrated contains a snapshot: If it does, you need to delete the snapshot before performing the migration.
• Clean up non-essential virtual peripherals, such as USB passthrough devices, ISO images, etc., on the VMs to be migrated.
• Uninstall the VMware VMTools on the VMs to be migrated.

Step 4 — Pre-migration

Users can select a VM template in VMware clusters and migrate it to the destination cluster using the migration tool. Pre-migration allows you to verify if the entire migration process is smooth and efficient. In this phase, you can obtain information such as VM disk capacity, migration speed, migration time, etc., and use it as a reference for the formal migration.

Step 5 — Formal Migration

With Arcfra Migration Tool, the formal migration involves the following steps:

• Select VMs to be migrated: Select the VMs to be migrated (one or more concurrently) according to the migration plan.
• Select target cluster and host: If there are multiple ACOS clusters on your site, select the appropriate cluster as the target cluster based on resource utilization.
• Select the virtual network: Generally, select the same subnet as the original VM. If there are multiple virtual NICs, they should correspond to each other as needed to ensure normal communication on the virtual network after the migration is completed.
• Full copy transfer: The data transfer phase requires a complete copy of the virtual machine’s disk data over the network, and the whole process takes a long time. In case of network interruption during the transfer, you can use the Arcfra Migration Tool’s breakpoint resumption function to ensure the continuity of VM migration.
• Incremental data synchronization: When data transfer is completed, users can choose to manually synchronize the incremental data and then shut down the source VM. After shutdown, the migration tool will automatically synchronize the remaining incremental data and perform the necessary driver injection and system configuration operations.
• Check target VMs: After the migration is completed, users should check the new VMs in the ACOS cluster to ensure that the operating system can be logged in normally, the network can communicate normally, the virtual disks have all been mounted normally, and the critical applications can run normally.

If the VM cannot complete the migration normally, or the business systems cannot run normally after the migration, you can try to roll back the migration.

• Log in to the Arcfra Operation Center (ACOS UI) and shut down the migrated VMs in the ACOS cluster.
• Log in to the original VMware vCenter, locate the original VM, and restart the VM.
• Check if the VM can be logged in and the business system can provide services properly.

Looking to dive deeper into VMware migration? Check out our related articles for practical tips, tech insights, and alternative solutions:

How to Improve VMware Migration Efficiency? Test with Arcfra Migration Tool: 100 + VMs Migrated In 5 Days

Accelerating Your VMware Migration: The Tech Behind Arcfra Migration Tool

Top 5 VMware Alternatives in 2026–2027

Navigating the VMware Shake-Up: A Must-Read Guidebook for VMware Replacement